In order to solve the problem of massive amount of computation brought by the numerical dynamic response simulation of soil-structure nonlinear interaction (SSI) system, the parallel computing method using SSI load balanced and dual-graph theory based domain decomposition (DD) algorithm is proposed. Combined with traditional greedy and recursive coordinate bisection algorithm, the parallel performance of these four algorithms is researched. The SSI is dealt with symmetric penalty method. The system equation is solved using finite element method (FEM) with explicit central difference scheme. The dynamic responses of typical engineering problems with SSI are simulated in parallel, and the scalability of these four algorithms is analyzed. The results indicate that the SSI load balanced algorithm which substantially balances the coupling loads of soil and structure shows the best parallel efficiency, followed by dual-graph theory based algorithm and recursive coordinate bisection algorithm, and the greedy method get the lowest parallel efficiency; the parallel efficiency decreases with the increasing cores, and the number of cores should be chosen properly according to the scale of the actual model to achieve the optimal parallel performance; the explicit FEM with penalty method is a proper approach for SSI dynamic analysis.

 

A novel two-degree-of-freedom piecewise-linear piezoelectric energy harvester was proposed to achieve wide operation frequency bandwidth. The theoretical model was established and the analytical solutions were given for the further optimize design and microminiaturization fabricating of the proposed device. Through the prototype fabricating and the experiment platform building, the experiment results were obtained. The analytical results and experiment results showed that The operation frequency bandwidths of the proposed device in the first resonance region and in the second resonance region were 2.2Hz and 4.5Hz respectively, the total bandwidth was 6.7Hz, which reached as 4.78 times as the corresponding linear system. Within the margin of error, the analytical solutions were close to the experiment results, and the proposed device could extend the bandwidth of the operation frequency efficiently.
 

In order to investigate the flow charateristics of residual heat removal pump under multi conditions，three-dimensional unsteady numerical simulations were conducted by using the SST turbulence model in ANSYS CFX．The performance、inner flow fields and pressure fluctuation of the residual heat removal pump under muiti conditions was obtained and compared with the experimental results．The results show that：the inner flow keep regular under 1.2Qd and 1.0Qd．However，with the decrease of the flow rate，The stall vortex generates near the suction side at the impeller and diffuser inlet associated with the onset of varying degrees of flow separation in the flow channels，which is intensified toward the outlet．The main frequency of pressure fluctuation at the outlet of impeller affected by the number of vanes is 7fz．The main frequencies at the outlet of both difusser and volute is 5fz，which are the blade passing frequency．The amplitudes of fluctuating pressure coefficient in all the monitoring points reach its minimum value under design condition，which increase gradually with the decrease of flow rate．It is concluded that the flow instabilites inside the pump occurs under small flow rate condition．
 

Structural displacement amplification factor (DAF) is the key factor in seismic design, which is used to predict maximum inelastic deformations of structures under earthquake excitation. However, DAF hasn’t been introduced in the current Chinese seismic design code. In this paper, 15 RC frame buildings which are 3-, 5-, 8-, 10-, 12-story buildings in different seismic fortification intensity VI, VII, VIII are designed according to the Code for Seismic Design of Buildings GB 50011-2010. The FE models of these buildings are modeled and structural seismic response is analyzed. Shaking table test of a RC frame structure has been accomplished and the FE models are verified and validated. The “demand” values of the structural DAF of these RC frames are evaluated by dynamic capacity spectrum method, and the analysis results are compared with that analyzed by traditional static capacity spectrum method. For the designed RC frames in the seismic fortification intensity VI, VII, VIII zones, the ranges of demand values of structural DAF are 0.51~1.91、0.49~1.93、0.56~2.24 respectively when they are under fortification earthquakes．The ranges of demand values of structural DAF are 1.18~4.05、1.33~3.45、1.42~2.66 respectively when they are under rare earthquakes．The overall yield of the codified designed RC frames under fortification earthquakes has not occurred, and it is shown that Chinese seismic design code is conservative.

The ballistic performance of a hybrid-cored sandwich structure was studied by using ballistic penetration test. Considering the failure modes and efficiency of absorbed energy, the anti-projectile mechanism of the hybrid-cored sandwich structure was synthetically analyzed. The experimental results indicate that anti-projectile capability is substantially enhanced in a high-amplitude extent. During the penetration of the spherical projectile, the kinetic energy of the projectile is absorbed mainly through the large plastic deformation and shearing expansion of the pyramidal lattice structure, the fracture failure of ceramics rods and hybrid epoxy, and the macroscopically bending deformation of the faces. The results can offer some helpful references for the protection design of lightweight composite armor.
 

To study dynamic characteristics and impact damage of mining scraper under different working conditions and chain speeds, the finite element model was established of scraper system which specifications was 26×92，the dynamics characteristic of scraper wad simulated and analyzed under different working conditions and chain speeds by using transient and explicit dynamics analyse module of ANSYS Workbench，and analyzed the impact damage of scraper by nCode GlypWorks under start-up conditions, the mechanical properties of scraper were obtained under variable conditions which included both running smoothly and starting under no-load or full-load, what’s more, we could obtain the rules of influence of time course for maximum equivalent stress of scraper with different speeds, acquired the degree of damage which was caused by starting impact loading under no-load or full-load. The simulation results show that, the scraper has good mechanical and anti-impact properties, provided an universal method to research the dynamic characteristics and impact damage of scraper with different specifications.
 

A kind of planar spring with four permanent magnet structure of vibration energy collector is designed based on the vibration and electromagnetic theories. The vibration picking system and energy conversion system of the structure are analyzed through theory and simulation. The overall design of the subsequent interface circuit is discussed and the corresponding circuits are optimized by simulation. The performance of the device is tested by experiment to verify its validity and reliability. Experiment results show that the interface circuit output voltage can reach to 9V within 0.25s. Then, the voltage comparison circuit generates a trigger signal to turn on analog switch so that the devices can work normally，which verifies the reliability of the system.
 

In this study, an in-plane direct impact experiment is designed using a rod and a plane. Three methods are studied in measuring the responses of the experiment, Laser-Doppler-Vibrometer, strain gauge and high speed camera system. The advantages and disadvantages of the three methods are analyzed. The experiment indicates that LDV and strain gauge could measure the velocity and strain of a single point accurately, while the two-dimensional high speed camera could measure the velocity and strain of whole pattern, which show the development of strain during the contact. The results demonstrate the applicability of the high-speed camera in the research of low-speed impact. However, after the contact period, there are some obvious wave errors in the strain and velocity results of the two-dimensional high speed camera, owning to the out-plane displacements which may be caused by the vibration of plate.

 

An issue of dynamic stress concentration for shallow buried circular cavity in a soft layered half-space under steady SH-Wave has been studied based on complex function and wave function expansion method, and analytical solution is obtained. According to the attenuation characteristic of SH-Wave scattering, using large-arc assumption method, that is, straight boundary of the surface layer is approximated by a circle with large radius, which lead to a surface boundary problem. Firstly, the general forms of unknown wave function are given on the basis of Helmholtz theorem. Then, according to the boundary conditions and the complex Fourier-Hankel series expansion method, the problem is transformed into the infinite linear algebraic equations of the unknown coefficients in the solution of the wave function. From the finite terms, the numerical results can be obtained. The sample analyze the influence on distribution of dynamic stress concentration factor around shallow buried circular cavity in a soft layered half- space when SH-Wave is normal incidence, including the wave number difference between overburden layer and half space medium in different incident frequency, the variation on the cover thickness and the buried depth of the circular cavity.
 

 

In order to predict the modal of a composite leaf spring in a light bus and estimate if the resonances among the modal of the composite leaf spring and the excitations will occur or not，the finite element model for the modal analysis of the composite leaf spring was established by using ABAQUS software. The computational modal analysis for the finite element model was carried out and the modal of the composite leaf spring was predicted according to the result of the computational modal analysis. Then the experimental modal analysis for the prototype of the composite leaf spring was carried out. The veracity of the prediction modal and the correctness of the finite element model are validated by the comparison between the prediction modal and the results of the computational modal analysis. According to the modal analysis results，the composite leaf spring can avoid resonances. The relationships among  design variables and the first-order modal frequency of the composite leaf spring are respectively analyzed by using the finite element model，which has been validated. The analysis results indicate that choosing 0°ply orientation，choosing composite that possesses lower density and choosing higher fiber volume content can reduce the possibility of resonances. The research results in this paper can significantly reduce the risk and the cost in the development of composite leaf spring.
 

Obtaining the mechanical parameters of hard coating is the premise of modeling and damping design of hard-coating composite structure. The most studies about identifying the mechanical parameters of hard coating are based on beam specimen and a complex test procedure. Here, a cantilever thin plate structure was considered, and a newer identification method was presented, which only needs to test the free vibration decay responses from resonance status for the uncoated and coated plate. Firstly, based on the free vibration decay responses, the principles of identifying storage modulus and loss factor of hard coating were proposed. Then, to effectively obtain the mechanical parameters of hard coating, the method of identifying some key parameters (such as envelop of response, instant resonance frequency and damping) was given. Next, the FEM modeling of hard-coating plate and solution of resonance frequency, modal strain energy and reference strain were described. Finally, the cantilever thin plate coated NiCoCrAlY+YSZ hard coating was chosen to display the proposed method and the storage and loss factor of this mixing coating were identified. Furthermore, the obtained material parameters were inputted into the created FEM model and the rationality of identified parameters was proved by comparing the first 6 orders resonance frequency obtained by measurement and FEM calculation respectively. The identification results show the change rules of storage modulus and loss factor of hard coating with the strain amplitude are almost consistent with the results listed in the other similar references. However, the results herein can more directly serve for the dynamic modeling of hard-coating plate-shape composite structure.
 

 

The energy approach is applied to study on the vehicle rollover-stability, and a new comprehensive evaluation method for vehicle rollover-stability is proposed. In order to study this methodology, a 10-DOF vehicle model with nonlinear characteristic is presented, and the comparison of vehicle road test and simulations with vehicle model verified that the model is correct. The rollover-stability index is provided: By calculating the ratio of real-time energy reserve and rollover energy threshold, the rollover energy reserve coefficient (RERC) can be deduced. And the velocity-steering interference coefficient (VSIC) is defined by integrating the vehicle velocity and the steering angle. After then, the comprehensive evaluation index of vehicle rollover stability, which contains the vehicle velocity, roll angle velocity, roll angle and tire steering angle, is established. Furthermore, the presented method is compared with the other vehicle rollover-stability evaluation method by different situation simulation experiments. The result shows that the presented method is correct and applicability. 
 

Because of the variable stiffness and damping characteristics of the hydro-pneumatic suspension, it has been widely used in heavy vehicles. But the conventional hydro-pneumatic suspension cannot adjust to fulfill the requirements of vehicle ride comfort based on the road conditions. In this paper, an active control method is proposed based on conventional hydro-pneumatic suspension. After modeling and experimental validation of the hydro-pneumatic spring, a quarter dynamic model of vehicle active hydro-pneumatic suspension is established and then using fuzzy-pid to control the active hydro-pneumatic suspension. It is co-simulated with AMESim and MATLAB. The simulation results show that the vehicle acceleration is reduced obviously and the ride comfort characteristics are improved comparing with passive suspension.
 

A typical marine shafting test bench was investigated in this paper. A finite element model of the shafting was established based on FEM and verified by tests. Natural characteristics of the shafting with main engine vibration isolation were analyzed. Lateral rolling was predigested as equivalent variational acceleration of gravity. It was applied to FEM model for the transient response analysis as boundary conditions. The computation results indicate that main engine vibration isolation reduce the natural frequencies of the whole system but makes no difference to those of shafting. Transfer forces and displacements at coupling increased and transmitted to shafting, causing much stronger vibration of shafting.
 

The impact experiment of underwater self-excited pulsed jet device was conducted by circulation experiment system of underwater jet. The impact time domain waveform were got. The time-frequency characteristic of impact was extracted by the method of integrating the second generation wavelet with Wigner-Ville distribution. The energy distribution law of impact frequency band was studied in inspiration and non-inspiration conditions, different confined pressure and target distance. The results show that there exists optimal below nozzle diameter that can make the impact time domain characteristic parameters maximizing. The impact energy of device mainly concentrates on low frequency band. Confining pressure, standoff distance and inspiration have large influence on frequency band energy. Inspiration has obvious influence on the impact frequency components, energy density distribution and pulse effect, but confining pressure and standoff distance only have great influence on the impact energy density distribution and pulse effect. The pressure of collision body measuring point reflects the state of energy accumulation and energy release of device, and has corresponding relationship with the impact energy density distribution.